Engine bucking & not shifting in heavy rain
03-31-2019, 04:57 PM
#1
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Model: Cherokee (XJ)
Engine bucking & not shifting in heavy rain
2000 XJ 4.0L automatic 4x4 155000 miles
A month ago we had heavy rain and my Jeep starting bucking randomly and wasn't shifting until way past the shift points.
CEL came on and I replaced the throttle position sensor and cleared the codes.
Then we had more rain and it happened again, this time I wrote down the codes and they were:
P0121
P1281
P0123
The rain stopped, I cleared them and it returned to normal driving.
Then we had heavy rain again the past few days and it came back worse than ever with more codes. The bucking seemed to get worse the more I would try to give it gas. This time the codes I got were:
P0123 (2x)
P0700
P0121 (2x)
P0122
P0740
This time when I tried to clear the codes only some of them cleared.
My buddy said to use a spray bottle under the hood with the engine running to see if I could trigger the problem. I didn't have a sprayer but I slowly poured some water on what I thought was the coil pack bar and the rpms dropped but no bucking. The only thing is that what I poured the water on was on the right side of the motor (opposite from the coil pack). It was the long plastic bar running next to the fuel rail with the wires connecting to the injectors. I bought a new coil pack thinking that's what I had drenched with water.
What is this bar called?
I am home now, should I try the spray bottle trick again? Should I just swap out the coil pack anyway? Do I need to make sure the engine is dry before removing the old coil?
Could this actually be my transmission control module or should I check everything else first? Is it ok to spray water on the TCM, and will that do anything as far as diagnosis if it is just in park?
Thanks so much
A month ago we had heavy rain and my Jeep starting bucking randomly and wasn't shifting until way past the shift points.
CEL came on and I replaced the throttle position sensor and cleared the codes.
Then we had more rain and it happened again, this time I wrote down the codes and they were:
P0121
P1281
P0123
The rain stopped, I cleared them and it returned to normal driving.
Then we had heavy rain again the past few days and it came back worse than ever with more codes. The bucking seemed to get worse the more I would try to give it gas. This time the codes I got were:
P0123 (2x)
P0700
P0121 (2x)
P0122
P0740
This time when I tried to clear the codes only some of them cleared.
My buddy said to use a spray bottle under the hood with the engine running to see if I could trigger the problem. I didn't have a sprayer but I slowly poured some water on what I thought was the coil pack bar and the rpms dropped but no bucking. The only thing is that what I poured the water on was on the right side of the motor (opposite from the coil pack). It was the long plastic bar running next to the fuel rail with the wires connecting to the injectors. I bought a new coil pack thinking that's what I had drenched with water.
What is this bar called?
I am home now, should I try the spray bottle trick again? Should I just swap out the coil pack anyway? Do I need to make sure the engine is dry before removing the old coil?
Could this actually be my transmission control module or should I check everything else first? Is it ok to spray water on the TCM, and will that do anything as far as diagnosis if it is just in park?
Thanks so much
03-31-2019, 06:35 PM
#3
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Year: 1997
Model: Cherokee
Engine: 4.0L
2000 XJ 4.0L automatic 4x4 155000 miles
A month ago we had heavy rain and my Jeep starting bucking randomly and wasn't shifting until way past the shift points.
CEL came on and I replaced the throttle position sensor and cleared the codes.
Then we had more rain and it happened again, this time I wrote down the codes and they were:
P0121
P1281
P0123
The rain stopped, I cleared them and it returned to normal driving.
Then we had heavy rain again the past few days and it came back worse than ever with more codes. The bucking seemed to get worse the more I would try to give it gas. This time the codes I got were:
P0123 (2x)
P0700
P0121 (2x)
P0122
P0740
This time when I tried to clear the codes only some of them cleared.
My buddy said to use a spray bottle under the hood with the engine running to see if I could trigger the problem. I didn't have a sprayer but I slowly poured some water on what I thought was the coil pack bar and the rpms dropped but no bucking. The only thing is that what I poured the water on was on the right side of the motor (opposite from the coil pack). It was the long plastic bar running next to the fuel rail with the wires connecting to the injectors. I bought a new coil pack thinking that's what I had drenched with water.
What is this bar called?
I am home now, should I try the spray bottle trick again? Should I just swap out the coil pack anyway? Do I need to make sure the engine is dry before removing the old coil?
Could this actually be my transmission control module or should I check everything else first? Is it ok to spray water on the TCM, and will that do anything as far as diagnosis if it is just in park?
Thanks so much
A month ago we had heavy rain and my Jeep starting bucking randomly and wasn't shifting until way past the shift points.
CEL came on and I replaced the throttle position sensor and cleared the codes.
Then we had more rain and it happened again, this time I wrote down the codes and they were:
P0121
P1281
P0123
The rain stopped, I cleared them and it returned to normal driving.
Then we had heavy rain again the past few days and it came back worse than ever with more codes. The bucking seemed to get worse the more I would try to give it gas. This time the codes I got were:
P0123 (2x)
P0700
P0121 (2x)
P0122
P0740
This time when I tried to clear the codes only some of them cleared.
My buddy said to use a spray bottle under the hood with the engine running to see if I could trigger the problem. I didn't have a sprayer but I slowly poured some water on what I thought was the coil pack bar and the rpms dropped but no bucking. The only thing is that what I poured the water on was on the right side of the motor (opposite from the coil pack). It was the long plastic bar running next to the fuel rail with the wires connecting to the injectors. I bought a new coil pack thinking that's what I had drenched with water.
What is this bar called?
I am home now, should I try the spray bottle trick again? Should I just swap out the coil pack anyway? Do I need to make sure the engine is dry before removing the old coil?
Could this actually be my transmission control module or should I check everything else first? Is it ok to spray water on the TCM, and will that do anything as far as diagnosis if it is just in park?
Thanks so much
Codes P0120, P0121 and P0123 are the TPS. What brand TPS? If its is not Mopar, it is suspect. Check the connections for corrosion and make sure its a good solid connection. Do you have hood vents? The TPS can get wet if so, and it will start acting funny. The P0700 doesnt really tell you anything, except that the TCM has encountered a fault. Could be anything. The P0740 i believe is the torque convertor? I have read where another had the same code and a new TPS fixed it. Another changed transmission fluid. The P01281 means the engine was too cold for too long, but i wasnt aware the XJ encountered this code? I have only seen this on the Grand Cherokee. My moms 2018 had it once. Faulty thermostat.
03-31-2019, 06:49 PM
#4
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Model: Cherokee (XJ)
The TPS is from O'Reilly's. I can change it out again and see if it helps.
I do have hood vents but small ones, not the entire hood. I do think heavy rain could get on the TPS though.
The TPS is from O'Reilly's, but it isn't very old. I can swap it out tomorrow to see if that helps.
I do have hood vents but small ones, not the entire hood. I do think heavy rain could get on the TPS though.
The TPS is from O'Reilly's, but it isn't very old. I can swap it out tomorrow to see if that helps.
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